The invention relates to a device for blocking the steering shaft of a motor vehicle against rotation by means of a locking bolt, which is movable axially back and forth between a locked position and a released position in a housing via a control member that can be rotated back and forth. The locking bolt comprises a locking element and an actuating element, and the control member surrounds the actuating element and has two helically extending interior grooves as well as a plane end surface, adjoining the grooves and perpendicular to the axis of rotation of the control member, with which grooves and end surface a transverse pin that is axially displaceable in a transverse bore of the actuating element cooperates, and the locking element is adapted to be pushed into the actuating element against the action of a helical compression spring.
Such a device is known (German Patent 100 30 688 C1). Therein, the actuating element of the locking bolt and the control member cooperate in such a way that upon rotation of the control member in that direction in which the two ends of the transverse pin, which protrude from the transverse bore of the actuating element, run in the grooves of the control member toward its end surface that is bounded by a side flank extending toward the actuating element from the bottom of one groove outside and past the other groove at a distance from it, the actuating element is correspondingly displaced axially, so that whenever the ends of the transverse pin make a transition from the grooves to the end surface, the actuating element is stopped and remains in the axial position it has reached, until the control member is rotated in the opposite direction and the ends of the transverse pin move in the grooves away from the end surface, so that the actuating element is displaced axially in the opposite direction. The ends of the transverse pin are pressed against the end surface by a disk spring or helical spring, provided between the end of the actuating element remote from the locking element of the locking bolt and the closure cap of an assembly opening of the housing of the device, so that upon rotation of the control member in the aforementioned opposite direction, they readily enter into the grooves.